Extruded article and device for making same



June 6, 1939.

R. P. PIPEROUX EXTRUDEDARTICLE AND DEVICE FOB MAKING SAME 2 sheets-sheet 14 Fi-led March 22, 1935 INVENTOR Rene P Piperoux mu 5 No om June `6, 1939. l R. P. PlPl-:Roux 2,161,588

EXTRUDED ARTICLE AND DEVICE FOR MAKING SAME Filed March 22, 1935 2 SheetS-Sheet 2 l 'INVENTOR Rene .0. Piperoux A RNEYS Patented June 6, 1939 UNITED STATES PATENT OFFICE EXTRUDED ARTICLE AND DEVICE FOR MAKING SAME Rene Piperoux, ltadburn, N. J., assignor to. Celluloid Corporation, a corporation o! New Jersey Application March 22,

8 Claims.

1 1 thereon due to the material spewing at the joint of the mold sections. Another object of this invention is the` construction of a device for the formation of molded articles by the extrusion method, which device is so constructed that the y 1: articles produced are of a true shape and contain no heavy skirt or edge that would require cutting off. 'I'he latter necessitates a waste'of material and/or grinding smooth to a true shape,

making for an added, expensive operation in the production of an article. Other objects of the invention will appear from the following detailed description and drawings.

In the drawings, also forming a part of this invention, wherein like reference numerals refer Ato the same or similar elements in the various figures Figure l is a plan view of a device constructed according to this invention. Y

Fig. 2 is a side elevation, partly in section of the device shown in Fig. 1.

Fig. 3'is al view in elevation taken on the line 3 3 of Fig. 2. v

Fig. 4 is an end view in elevation of the device shown in Fig. l.

By employing this invention, the Waste normally caused by material forcing the mold faces apart, thus spewing andA forming a skirt or fin on the4 object and also forming `imperfect articles that must be thrown away or classed as seconds m is eliminated by keeping the two halves oi the die always in close contact as the plastic material is forced into the mold. This is accomplishedv by applying a hydraulic or any uid pressure on the mold tending to hold the mold faces together l such that the applied pressure is greater than the pressure used in forcing or extruding the plastic material into the mold.

By employing this invention there may be formed'by extrusion methods substantially perfect articles. The closing apparatus of the mold or die faces is so made that when pressure is applied within the mold or die by the i-nJection of the plastic material, opening of the die is resisted byv means of hydrulic or any uid pressure, the halves of the dies being so hooked up that under theA 1935, Serial N0. 12,369

(Cl. 18-30) I tremendous pressure obtained, any lengthening of the die tie rods is immediately compensated by a following up of. the die, thus permitting the die to remain closed entirely` independent of extension or contraction of the metal parts under load -or strain.

In accordance with my invention, I construct an extrusion molding device containing two opposing fiuid pressures operating from opposite sides of a moving mold or die face, which mold or die face cooperates with a stationary'mold or die face, the opposing fluid pressures being such that, during extrusion, there is a greater pressure operating on the back of the moveable mold or die face .tending to hold the two mold faces together than the pressure operating to separate the mold faces. 'Ihe arrangement and construction of the pressure 'producing mechanisms are such that a creeping of the various parts is permitted, allowing for expansion, elongation or contraction of the metal i`n parts under load or strain, without disrupting the applied pressures on the mold.

This invention is applicable to the forming of articles by the extrusion method, which articles are formed from thermoplastic or thermosetting. materials containing organic compounds. For instance, this invention is particularly applicable to the formation of articles from thermoplastic resins such as those formed by the condensation of polyhydric alcohols with organic'acids in such a manner as to possess the properties of being thermoplastic or weldable by the action of pressure and/or heat and to such resinous-like materials' as chlorinated rubber, polymerized vinyl compounds, etc. Thisinvention is also particularly adaptable to the formation of molded articles from thermoplastic materials containing derivatives of cellulose, for instance, cellulose nitrate ofr any degree of nltration. the organic esters of cellulose and the cellulose ethers. Examples of organic esters of cellulose are cellulose acetate, cellulose formate, cellulose propionate and cellulose butyrate, while examples of cellulose ethers are methyl cellulose, ethyl celluose and benzyl cellulose.

When employing such thermoplastic materials as the derivatives of cellulose, the same may be ground into a i'lne state of subdivision, in the presence of various eiiect materials, into a compound known in the art as press mass powder. The eilect materials that may thus be combined with the thermoplastic derivatives of cellulose are plasticizers, pigments, fillers, dyes and lakes, etc. Any suitable method and means may be employed for forming the press mass powders, for instance, there may be employed the methods and materials described in U. S. Patents Nos. 1,732,330, 1,871,

670, 1,910,948, 1,942,090, 1,980,326, 1,987,610, I 1,930,069, 1,899,542 and 1,899,053.

As a means of visualizing the invention the same will be described with reference to the device shown in the drawings, which device also forms a part of this invention. The device conl sists of a main frame I supported by suitable legs 2. This', main frame may be of any suitable construction capable of withstanding the weight and vibration of the device. This mainframe is preferably in the form of a table, the edges of the top of the same'being formed of angle iron or other suitable material. This table is adapted to support a plurality of pistons and a setof die faces for the purpose of forming articles from y plastic materials by the extrusion method of cast- Il ing. v v There may be suitably fastened on to the main frame or table I a standard 3 Vhaving a yokev member -or breast plate 4, which may be formed thereon or joined thereto, a mold face 5 is fastened to the yoke member-and hasan opening l adapted to receive the nozzleof an extrusion de- Y There may be provided on the table I a standn ard II, .which standard may be slldably connected thereto as by means of a lug bolt I2 operating in a groove or slot in the top of the table. 'Ihis standard I I and the standard 1 support a cylinder I3 ,-whicli cylinder may contain a piston I4 a adapted to drive a piston rod I5 attached to a die face I6. The die face I9 and the outer end ofv piston rod I5 may be supported by yoke I1 adapted to slide upon the main tie rods I0 of the device. For operating the piston there may o be provided a source of fluid pressure I9 adapted to exert pressure behind the piston to move the same and the die face I6 forward to contact with the die face 5. A suitable source of fluid pressure I9 is provided for forcing the piston inward- 55 ly, thus separating the die faces I9 and 3. For the purpose of automatically ejecting formed pieces from between the mold faces 5 and I3, there is provided a yoke 23 carrying within it a long threaded member 22, going through a packed 00 joint in the cylinder I3, through the piston rod I5, Land yoke I1, and extending into the die block I3 and bearing against a standard type of knockout plate. The purpose of threading member 22 is to permit of making an adjustment in its v(u, length relative to the die block I9 so that when 75 and heldin adjusted position by means of lockV or other suitable rods.

device. Also carried by the standards 23 and 24 are two similar cylinders which may be positioned one on each side of and in the horizontal l0 piane passing through the center of the main cylinder 26. Each of the cylinders 30 is provided with a piston 3l connected by a piston rod 32 to a yoke member 33 that is adapted to ride on and slide along the main tie rods I0. Yoke member l5 33 may be connected with a similar yoke member 34, also adapted to ride on main tie rods I0, by means of connecting 'rods 35, which connecting rods may be an extension of the piston rods 32 The yokes 33 and 34 with 20 their connecting rods 35 form a carriage adapted to be moved back and forth along the main tie rods Il. The carriage thus formed may be provided with a hopper 36 connected to a nozzle 31. The material 4to'be molded, for instance, press 25 mass powder, may be fed to the hopper 36 which in turn feeds the material to the nozzle 31 thatv is adapted to register with the receiving opening 6 inthe mold face 5. Both the nozzle 31 and the hopper 35 may be provided with heating or cool- 30 ing elements, thermostatically controlled if desired. For instance, these elements may be connected to a system for circulating fluids through jackets formed thereon or the same may be connected to a suitable source of electric current that 35 may operate inductance or resistance coils to melt the material justprior to being extruded into the cavity .of the mold formed between the mold faces 5 and IG. Y

A suitable sourceof fluid pressure 38 may be 40 provided for forcing the piston 21 forward, thus 'moving the plunger 29 in such a manner as to force the material out of the nozzle 31. A suitable source of fluid pressure 39 may be provided for withdrawing piston 21, thus pulling the plunger 29out from the nozzle 31 and permitting a. further charge of material to run or fall down into the nozzle 31 ready for extrusion on a subsequent stroke. Suitable ducts 40 may be provided for applying iiuid pressure to the pistons 3| for the purpose of moving the carriage and the nozzle 31 forward into registry with the opening rot the die mold. Suitable ducts 4I may be provided for applying fluid pressure to pistons 3I in such a manner as to pull the carriage 5,-, back from the mold face opening 8.

It will be further noted that the piston rod 28 terminates in a collar 4B having an adjustable section 42 that may be screwed into or out of the collar 45. T'he section 42 is adapted, on the w back stroke of the piston 21, to contact with a shoulder 43 on the yoke 33 to pull the carriage back. There is suillcient play left between the section 42 and shoulder 43 in order that the cary riage may be moved a short distance forward and 05 back with reference to the plunger 29 to pump or completely ll the nozzle.

In operation, fluid pressure is admitted through duct I3, forcing the piston I5 forward and closing the die faces 3 and I9. The hopper 36 having been fllled with a suitable thermoplastic material, fluid pressure is applied to the pistons 3I3I through the ducts 4I. As has been previously Stated, there is a lost or slack motion between the u yoke 33 and the piston rod 2l which enables the hopper and nozzle 33 and 31 to be drawn hack against ithe'cylinder 21 to such an extent as may be limited by this slack motion. This permits the packing of the thermoplastic material within this nozzle I1. This is repeated as many times as may be necessary by successive admission and release of the pressure through ducts 4i, each time taking a small charge of powder and thoroughly packing within the nozzle, without, however, exerting en'ough force thereon to extrude it through the nozzle 31. When the powder has been suitably packed, pressure is cut oil through ports 4i and admitted behind piston 3i by ducts Ill, pushing the hopper forward again to the forward limit of its motion on plunger 38, leaving the piston rod 29 retracted within the nozzle 31.

Pressure is now admitted through port 38 and since pressure still exists on the back of the piston 3i, the whole assembly will go forward together until such time as the nozzle 31 enters the opening 6 in the mold face and is positioned against the mold, at which time further motion of the nozzle 31 is stopped, it being held firmly on Athe mold face by the pressure behind piston 3|.Y However, pressure still being exertedbehind piston 29"(via port 38) the piston 29 will continue to go forward within the nozzle 31, forcing the material into the mold. It will be noted that pistons 3| are relatively small, so that the pressure exerted by the nozzle 31 against the die face is limited to such an extent as to reduce to a safe value the unit pressure on nozzle 31 which would otherwise be crushed. However, the pressure admitted behind piston 23, because of its iarge area, is relatively greatpermitting high pressures within the moldwithout subjecting vtrie nozzle tip to undue strain.

It will be noted that the area of the piston 'i3 is considerably larger than the area of the piston 21. This arrangement provides for the nonopening of the mold faces during extrusion of material into the mold. Thus, the proJected area of the piece being extruded in a line at. right angles to the axis of the machine, multiplied by the pressure per sq. in. existing within the nozzle (and therefore within the mold) will. be no greater than the unit pressure per sq. in. within the cylinder I3, multiplied by the area of the piston Il. Since some pressure within the nozzle 31 is lost going through the ports of themold, the above conditions will be obtainedv only when the material is exceedingbY fluidin which case fluid pressures andvtheir laws will govern. Actually, it is my experience that the unit. pressure per sq. in. existing within the mold during usual extruding conditions is only about W3 'the pressure per sq.'in. existing within the nozzle. This is. of course, approximate. More fluid material will give greater pressures and less fluid material, lower pressures.

- By employing'this device, the mold faces I6 and 5 are held inclose position by means of the iluid pressure in the cylinder l3,'which cyllnder I3 is attached to themain tie rods i0 of the device, so that when the machine is in operation any elongation of the metallic parts, such as tie rods Ill, plunger 23, etc., is compensated by the maintenance of a constant pressure on the die or mold face i 6. Thus, any creeping of the cylinders due to the elongationof the tie rods is fully compensated by 'the movement of the piston Il and the cylinder i3, so that there is always maintained on the die face i6 pressure which is inadequate to prevent the separation of the mold sections.

It is to be understood that the foregoing detailed description and drawings are given merely by way of illustration and that many variations may be made therein without departing from the spirit of my invention.

Having described my invention. what I desire v to secure by Letters Patent is:

l. An extrusion moldiniir device for molding organic thermoplastic substances, comprising a hopper for holdinga supply of material, a nozzle connected to said hopper, a sectional mold adapted to receive the material from said nozzle, a plunger in said nozzle, fluid pressure means for operating said plunger, a second fluid pressure means operatively connected to a section of themold remoto from said nozzle and adapted to hold the sections of the mold together, means binding the two fluid pressure means together and fluid pressure means for registering said nozzle with, and holding said nozzle against, said mold, under a pressure which is less than the pressure employed for holding the mold sections together.

2. An extrusion molding device for molding organic thermoplastic substances comprising a hopper for holding a supply of material, a nozzle connected to isaid hopper, a sectional mold adapted to receive the material from `said nozzle, a plunger in said nozzle, a fluid pressure cylinder, a piston in said cylinder operatively connected to said plunger, ,a second uid pressure means operatively connected to a section of the mold remote from said nozzle and adapted to hold the sections of the mold together, means binding the two fluid pressure 'means together and uid pressure means for moving said hopper and said nozzle to, and holding said nozzle against, said mold, under a ,pressure which is less than the pressure employed for holding the mold sections together. y

3. An extrusion molding" device for molding organic thermoplastic substances comprising a hopper for holding a supply of material, a nozzle connected to said hopper, a sectional mold adapted to receive the material from said nozzle, a plunger in said nozzle, a fluid pressure cylinder, a. piston in said cylinder operatively connected to said plunger, means for supplying operating fluid to either side of said piston, a second fluid pressure means operatively connected to a section of the mold remote from said nozzle and adapted to hold the sections of the mold together, means binding the two fluid pressure means together and fluid pressure means for moving said hopper and said nozzle to, and holding said nozzle against, said mold, under a pressure which is less than the pressure employed for holding the mold sections together. y i

4. An extrusion molding device for molding organic thermoplastic substances comprising a hopper for holdings supply of material, a nozzle connected to said hopper, a sectional mold adapted to receive the material from said nozzle, a plunger in' said nozzle, a iluid pressure cylinder, a piston in said cylinder operatively connected to said plunger, a second fluid pressure cylinder, a. second piston in said cylinder operatively connected to a section of said mold remote from said nozzle, means binding the two fluid pressure means together and fluid pressure meansV for moving said hopper and said nozzle to, and holding said nozzle against, said mold, under a presa carriage for supporting said hopper and nozzle,

a pistonin said cylinder operatively connected to said carriage for moving the said hopper and nozzle, to move and to hold said nozzle against, said mold, under a pressure which is less than the pressure employed for holding the mold sections together, a second iluid pressure means operatively connected to a section of the mold remote from said nozzle and adapted to hold the sections of the mold together and means binding the two uid pressure means together.

6. An extrusion molding device for molding organic thermoplastic substances comprising a hopper for holding a supply of material, a nozzle connected to said hopper, a sectional mold adapted. to receive the material from said nozzle, a plunger in said nozzle, fluid pressure means for operating said plunger, a plurality of fluid pressure cylinders, a carriage supporting said hopper and nozzle, pistons in said cylinders operatively connected to said carriage for moving the said hopper 'and nozzle, to move and to hold said nozzle against, said mold, under a pressure which is less than the pressure employed for holding the mold sections together, a second iluid pressure means operatively connected to a section of the mold remote from said nozzle and adapted to hold the sections of the mold together and means binding the two iluid pressure means together.

7. An extrusion molding device for molding organic thermoplastic substances comprising a hopper for holding a supply of material, a nozzle connected to said hopper, a sectional mold adapted to receive the material from said nozzle, a plunger in said nozzle, a iluld pressure cylinder, a piston in said cylinder operatively connected to said plunger, means for supplying operating fluid to either side oi' said piston, a pair of iluid pressure cylinders, a carriage supporting said hopper and nozzle, pistons in said pair of cylinders operatively connected to -said carriage for moving the said hopper and nozzle, to move and to hold said nozzle against, said mold, under a pressure which is less than the pressure employed for holding the mold sections together. a second fluid pres-. sure cylinder, a piston in said cylinder operatively connected to a section of said mold. remote from said nozzle for holding the mold together, means for supplying operating iiuid to either side of said piston and means binding the two fluid pressure means together.

8. An extrusion molding device for molding organic thermoplastic substances, comprising a hopper for holding a supply of material, a nozzle connected to said hopper, a sectional mold adapted to. receive the material from said nozzle, a.

plunger in said nozzle, iluid pressure means for operating saidplunger, iluid pressure means for moving and holding the mold sections together and for bringing and holding the mold and nozzle into registry and contact with each other, said last named means including means for exerting a greater pressure upon the mold sections for holding them'together than is exerted upon the nozzle for holding the latter in contact with -the mold.

RENE P. PIPEROUX.

CERTIFICATE OF CORRECTION. Patent No. 2,161, 588. .Tune 6, 1959.

RENE P. PlpERomi.

It is hereby certified that s rror appears in the printed specification of the above numbered patent requiringI correction as follows: Page l, first column,I line 5h, for "hydrulic" read hydraulic; page 5, se cond column, line l, for inadequate read adequate; and that the said Letters Patent should be read `with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 18th day of July, A. D. 1959.

Henry Van-Arsdale,

(Seal) Acting Commissione;` of Patents. 

